Removing connections from bulkhead!

Its called Ignition circuit, but it also feeds the alternator's rotor. Current splits at the ballast resistor.
This first pages of this booklet cover the regulator and alternator operation.
Alternators and Regulators (Session 228) from the Master Technician's Service Conference

and this page has a very brief overview the ignition system.
Ignition System Analysis (Session 259) from the Master Technician's Service Conference